I think GP meant “collaboratively” as in collaborating online through the game itself. The same way you might e.g. collaborate on a Google Doc.

“Sit down together” might be impractical here, if GP’s child’s friends are e.g. friends they made before a move, who are thus quite far away physically. Or friends with snobby parents who won’t let them come over to GP’s house for whatever dumb reason. Or friends with extra-curriculars such that their free time never lines up with GP’s kid’s free time—meaning that only async collaboration will work.

(That’s just a steelman position, though; in general I agree.)